Muscles 2

Muscles 2

McKinley and O’Laughlin

Chapter 12

Introduction

Muscles of the pectoral girdle and upper extremity may be classified into what 5 groups? Muscles that move the:

Pectoral girdle Glenohumeral joint Elbow/forearm Wrist, hand, fingers

Intrinsic muscles of the hand

Move the Pectoral Girdle

Name: Pectoralis minor Origin: ribs 3-5 (sternal ends) Insertion: Coracoid process of scapula Action: Pulls scapula forward and down

(protracts and depresses)


Name: Serratus anterior Origin: (External surfaces of) lateral parts of

ribs 1-8/9 (upper and middle) Insertion: Anterior vertebral border of

scapula Action: Pulls scapula forward and down

(protracts and depresses)


Name: Levator scapulae Origin: (Posterior tubercle of) transverse

process of C1-C4 Insertion: Superior vertebral border (near

superior angle) of scapula Action: Elevates scapula. Rotates glenoid

inferiorly.


Name: Rhomboid major Origin: Spinous process of T2-T5 Insertion: Vertebral border (from rhomboid

minor to inferior angle) of scapula Action: Adducts (retracts) and elevates

scapula. Rotates glenoid inferiorly.


Name: Rhomboid minor Origin: Spinous process of C7-T1 Insertion: Vertebral border (just below

spine) of scapula Action: Adducts (retracts) and elevates

scapula. Rotates glenoid inferiorly.


Name: Trapezius Origin: Medial superior nuchal line.

External occipital protuberance. Nuchal ligament. Spines of C7-T12.

Insertion: Acromial end of clavicle. Acromion. Spine of scapula.


Name: Trapezius Action:

Superior fibers: Elevate scapula Middle fibers: Retract (adduct) scapula Inferior fibers: Depress scapula Sup and Inf: Rotate glenoid superiorly

Move the Glenohumeral joint

Name: Latissimus dorsi Origin: Spines of sacral, lumbar and lower

thoracic vertebrae (thoracolumbar fascia). Iliac crest. Lower 4 ribs.

Insertion: Intertubercular groove Action: Extends, adducts, and rotates

humerus medially. Retracts shoulder.


Name: Pectoralis major Origin:

Clavicular head: Medial clavicle Sternocostal head: Anterior sternum. Superior

6 costal cartilages. Aponeurosis of external obliques.

Insertion: Crest of greater tubercle


Name: Pectoralis major Action:

Both heads: Adduct and medially rotate humerus. Draw shoulder anteriorly and inferiorly (protract and depress)

Clavicular head: flex humerus Sternocostal head: extend humerus


Name: Deltoid Origin: Clavicle. Acromion. Spine of

scapula. Insertion: Deltoid tuberosity Action:

Anterior: Flex and medially rotate humerus Middle: Abduct humerus Posterior: Extend and laterally rotate humerus


Name: Coracobrachialis Origin: Coracoid process of scapula Insertion: Medial humerus (middle 1/3) Action: Flex and adduct humerus


Name: Teres major Origin: Inferior angle and lateral (axillary)

border of scapula Insertion: Crest of lesser tubercle Action: Medially rotate, extend, and adduct

humerus


Name: Subscapularis Origin: Subscapular fossa Insertion: Lesser tubercle Action: Medially rotate humerus (extend

and adduct)


Name: Supraspinatus Origin: Supraspinous fossa Insertion: Greater tubercle Action: Abduct and laterally rotate humerus


Name: Infraspinatus Origin: Infraspinous fossa Insertion: Greater tubercle Action: Laterally rotate humerus


Name: Teres minor Origin: Lateral border of scapula (superior) Insertion: Greater tubercle Action: Laterally rotate humerus

Move the Elbow/Antebrachium

What separates the limbs into compartments? Deep fascia


What 2 compartments occur in the brachium? Anterior - (Flexors) Posterior - (Extensors)


Name: Biceps brachii Origin:

Short head: Coracoid process Long head: Supraglenoid tubercle

Insertion: Radial tuberosity. Bicipital aponeurosis.

Action: Flex and supinate antebrachium


Name: Brachialis Origin: Distal, anterior humerus Insertion: Coronoid process (ulna) Action: Flex antebrachium


Name: Brachioradialis Origin: Lateral supracondylar ridge of

humerus Insertion: Distolateral radius (styloid

process) Action: Flex antebrachium


Name: Triceps brachii Origin:

Long head: Infraglenoid tubercle Lateral head: Posterior humerus superior to radial

groove Medial head: Posterior humerus inferior to radial

groove Insertion: Olecranon process of ulna Action: Extend antebrachium

Long head: steadies abducted humerus

Pronate/Supinate

Name: Pronator teres Origin: Medial epicondyle of humerus. Coronoid

process of ulna. Insertion: Lateral radius (middle) Action: Pronate antebrachium

Pronate/Supinate

Name: Pronator quadratus Origin: Distal, anterior ulna Insertion: Distal, anterior radius Action: Pronate hand

Pronate/Supinate

Name: Supinator Origin: Lateral epicondyle of humerus. Crest of

ulna. Insertion: Proximolateral radius (distal to

tuberosity) Action: Supinate antebrachium


Name: Flexor group Origin: Medial epicondyle

Anterior, proximal ulna and radius, interosseus membrane

Insertion: Carpals, metacarpals, phalanges Action: Flex wrist and digits


Name: Extensor group Origin: Lateral epicondyle

Posterior ulna and radius, interosseus membrane Insertion: Carpals, metacarpals, phalanges Action: Extend wrist and digits


What is another name for the flexor retinaculum? Transverse carpal ligament


The flexor retinaculum of the wrist and the arch of the carpals form what structure? Carpal tunnel

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Palmaris longus tendon (cut)

Common flexor synovial sheath

(a) Carpal tunnel, anterior view

Flexor retinaculum covering carpal tunnel

Flexor pollicis longus tendon

Flexor carpi radialis tendonTrapezium

Median nerve

Flexor digitorum profundus tendon

Flexor digitorum superficialis tendon

Common flexor synovial sheath

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(b) Carpal tunnel, transverse section

Carpal tunnel

Median nerve

Palmaris longus tendon

Anterior

Common flexorsynovial sheath

Flexor carpi radialis tendon

Flexor pollicis longus tendon

Flexor digitorumprofundus tendons

Flexor retinaculumcovering carpal tunnel

HamateCapitateTrapezoid

Trapezium

Posterior

Flexor digitorumsuperficialis tendons

Intrinsic Muscles of the Hand

What group of muscles forms the thick, fleshy mass at the base of the thumb and work to abduct, flex, and oppose the thumb? Thenar group

abductor flexor

opponens


What group of muscles forms the thick, fleshy mass at the base of the 5th digit of the hand and work to abduct, flex, and oppose the 5th digit? Hypothenar group

abductor flexor

opponens


Within the hand, what group of muscles lies between the 1st and 5th digits? Midpalmar group


Name: Lumbricals Origin: Tendons of the flexor digitorum

profundus Insertion: Extensor expansions (dorsal tendons)

on digits 2-5 Action: Flex digits at metacarpophalangeal joints

and extend at interphalangeal joints


Name: Dorsal interossei Origin: Adjacent sides of metacarpals Insertion: Extensor expansions and bases of

proximal phalanges of digits 2-4 Action: Abduct digits 2-4

(Extends interphalangeal joints)


Name: Palmar interossei Origin: Palmar surface metacarpals 2, 4, and 5 Insertion: Bases of proximal phalanges of digits

2, 4, and 5 Action: Adduct digits 2, 4, and 5

(Extends interphalangeal joints)

Muscles 2

Education

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